1. Field of the Invention
This invention relates to a image generating method and apparatus. More particularly, it relates to a image generating method and apparatus for realizing efficient image transmission or storage.
2. Description of the Related Art
Among the conventional representative image generating apparatus, there is the JPEG (Joint Photographic Coding Experts Group) system standardized by ISO. It is known that if, with the use of this system, a larger number of bits are allocated, satisfactory encoded and decoded images can be furnished. However, if the number of bits for encoding is reduced beyond a certain value, block distortion proper to the discrete cosine transform (DCT) becomes outstanding to render the subjective image deterioration apparent.
In recent years, investigations into an encoding system in which an image is split into plural bands by a filter device, termed a filter bank, combined from a high-pass filter and a low-pass filter, and is encoded from one band to another. Among these encoding methods is a wavelet encoding.
This wavelet encoding is felt to be promising as a new technique which possibly takes the place of the DCT because it is free from a defect proper to the DCT that block distortion becomes apparent in case of high compression.
For example, the above-mentioned image compression system is used in an imaging device, such as an electronic still camera or a video movie. In this imaging device, the above-mentioned JPEG system or the MPEG (Moving Picture Experts Group) system is used, and DCT is resorted to as an image transformation system.
Meanwhile, in an electronic still camera or video movie, an image as photographed is converted, or worked on. In the electronic still camera or video movie, the photographed image is occasionally converted to a thumbnail image or converted in resolution for storage in a memory or display on a display device.
In the electronic still camera or video movie, a thumbnail image or a photographed image converted in resolution is frequently stored or displayed. It is therefore desirable that the thumbnail image or the image converted in resolution be stored or displayed highly efficiently.
The wavelet transform which splits the frequency spectrum of an image for image transformation, may be said to contribute to improvement of the efficiency of the encoding system. However, there lacks a product which fully exploits the features of the wavelet transform.
It is therefore an object of the present invention to provide an image generating method and apparatus whereby a thumbnail image or an image converted in resolution can be stored or displayed highly efficiently.
In one aspect, the present invention provides an image generating apparatus including image inputting means for inputting an image, image processing means for pre-processing the input image for generating a digitized image, band image splitting means for splitting the frequency spectrum of the digitized image to yield band-based band images, storage means for storing an intermediate image obtained based on the band images, and display control means for displaying the intermediate image in controlled manner on a display unit.
In the image generating device, configured as described above, an input image is pre-processed to generate a digitized image, which then is split by band image splitting means into one or more bands to generate band-based band images. An intermediate image obtained based on the band images is displayed in a controlled fashion on a display by the display control means of the image generating device.
Thus, with the present image generating apparatus, a band image can be displayed on the display unit as a thumb-nail image or as a contracted image.
In another aspect, the present invention provides an image generating apparatus including an image inputting step for inputting an image, an image processing step for pre-processing the input image for generating a digitized image, a band image splitting step for splitting the frequency spectrum of the digitized image into one or more bands to yield band-based band images, a storage step for storing an intermediate image obtained based on the band images and a display control step for displaying the intermediate image in a controlled fashion.
In the image generating method, configured as described above, an input image is pre-processed to generate a digitized image, which then is split by the band image splitting step into one or more bands to generate band-based band images. An intermediate image obtained based on the band images is displayed in a controlled fashion on a display by the display control step of the image generating method.
Thus, with the present image generating method, a band image can be displayed as a thumb-nail image or as a contracted image.
In still another aspect, the present invention provides an image generating apparatus including decoding means for decoding encoded data comprised of an encoder version of band images obtained on band splitting, band image synthesizing means for synthesizing decoded band images to produce a band-synthesized image, storage means for storing an intermediate image obtained based on the decoded band images, and display control means for displaying the intermediate image in controlled manner on a display unit.
In the image generating apparatus, configured as described above, the encoded data, which is an encoded version of the band images obtained on band splitting, is decoded by decoding means. The decoded band images are synthesized by band image synthesizing means of the image generating apparatus to generate a band-synthesized image. The intermediate image, obtained based on the band images, is displayed in a controlled fashion on the display unit.
Thus, with the present image generating apparatus, a band image can be displayed on the display unit as a thumb-nail image or as a contracted image.
In yet another aspect, the present invention provides an image generating method including a decoding step for decoding encoded data comprised of an encoded version of band images obtained on band splitting, a band image synthesizing step for synthesizing decoded band images to produce a band-synthesized image, a storage step for storing an intermediate image obtained based on the decoded band images, and a display control step for displaying the intermediate image in a controlled manner.
In the image generating method, configured as described above, the encoded data, which is an encoded version of the band images obtained on band splitting, is decoded by the decoding step. The decoded band images are synthesized by the band image synthesizing step of the image generating method to generate a band-synthesized image. The intermediate image, obtained based on the band images, is then displayed in a controlled fashion.
Thus, with the present image generating method, a band image can be displayed on the display unit as a thumb-nail image or as a contracted image.